Valve for gas systems

ABSTRACT

An improved ball valve ( 1 ), in particular for gas systems, comprises a tampering indicating seal ( 25 ) made by injection molding a synthetic or metal material into cavities ( 19; 21; 22 ) formed in the screw-clamping nut assembly ( 11, 13 ) and including a cap outer portion ( 29 ) which substantially covers the surface of the outer face of the nut ( 13 ) and/or extending ( 29 A) on the side surface or said nut ( 13 ).

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an improved ball valve,specifically designed for domestic and industrial gas systems, accordingto the preamble of claim 1.

[0002] Ball valves in general, and in particular for domestic andindustrial gas systems, can optionally comprise tampering indicatingmeans, designed to clearly indicate a possible tampering of the valvemanual operating elements, such as operating knobs, levers or the like,which will be hereinafter generically called “driving lever”, and whichare coupled to a screw element for rotatively driving a valve ballshutter, by geometrically engaging it, and being clamped on said scewelement by a clamping threaded nut engaged on a free threaded endportion of the screw element.

[0003] The above mentioned a geometric fitting is usually performed byproviding two parallel and opposite flat portions at the free threadedend of the screw element and a corresponding opening, having parallelsides coupled by portions of a circumference of a diameter correspondingto the screw outer diameter, through the lever, so as to engage theclamping nut on said threaded portions of the screw. In particular,after having assembled and locked the lever by the nut, between theinner circumference of said nut and said screw flat portions, two freechambers, closed at the bottom by the lever and freely communicating atthe top thereof with the outside, will be formed.

[0004] For meeting machining accuracy requirements, the outer threadedend of the screw is moreover formed with a blind hole which, uponassembling, is left free.

[0005] Starting from the above disclosed prior art ball valveconstruction, two approaches for indicating a possible tampering havenow been herein devised, the first of which provides to apply a coloredpaint drop or strip extending from a point of the nut side surface tothe adjoining underlying driving lever, thereby a tamper of the lever,i.e. an unthreading of the nut, would cause an visually detectablebreaking of the paint drop or strip.

[0006] However, in actual practice, such a visual detection of the paintdrop or strip breakings is hindered both by the small surface of thepaint drop or strip arid by the fact that said breaking usually consistsof a thin cross slit which, upon re-screwing the nut, would be notlonger apparent.

[0007] The main drawback of this approach, however, is that, thetampering can be easily concealed by simply applying a further paintstrip or drop on the broken slit.

[0008] The second approach, being adopted by the Applicant, provides touse a nut housing therein, at its outer end, a plastic material ringwhich, upon threading the nut on the screw, is self-threaded on thescrew to be clearly seen from the outside, Thus, upon unthreading saidnut, the plastic material ring, which is properly colored, disengagestherefrom to clearly indicate its tampering.

[0009] The above mentioned approaches, moreover, can be hardlystandardized by some Foreign State Authorities, for example based on theEuropean standard En 331/1998 stating a lot of requirements on visuallyshowing possible tamperings in ball valve.

SUMMARY OF THE INVENTION

[0010] Accordingly, the aim of the present invention is to provide aball valve in which it would be very easy to visually show possibletamperings thereof.

[0011] The above mentioned aim is achieved, according to the invention,by a ball valve having the features of claim 1.

[0012] Further advantageous embodiments are disclosed in the dependentclaims.

[0013] Claim 2 discloses a very simple embodiment of the invention,having a single anchoring cavity and providing an easily visuallydetectable anti-tampering seal, anchored in a reliable manner.

[0014] Claim 3 discloses a first modified embodiment including a doubleanchoring cavity.

[0015] Claim 4 discloses a triple anchoring chamber, providing a veryreliable anchoring or clamping of the valve anti-tampering indicatingmeans.

[0016] As disclosed in claim 5, the outer portion of the anti-tamperingmeans or seal extends through the overall outer face of the clampingnut, thereby it can be clearly univocally seen.

[0017] This vision facility and clearness is further improved by thesolution claimed in claim 6.

[0018] As disclosed in claim 7, the anchoring cavities provided hereinhave a small height thereby conventional or depressed clamping nuts canbe used.

[0019] As disclosed in claim 8, a plastic material or a low meltingmetal or metal alloy, such as a lead, tin alloy, can be used as theinjectable or molding material.

[0020] As disclosed in claim 9, it is possible to clearly visuallydetect a performed tampering.

[0021] Thus it should be apparent that the invention provides a lot ofimportant advantages, such as a visually clear indication of atampering. Moreover, upon tearing away, the anti-tampering seal cannotbe reconstructed thereby providing a permanent tampering indication.while the herein proposed anchoring cavities can be suitably dimensionedand shaped appropriately depending on their molding material, it isadvantageously possible to use the cavities already existing in priorball valves, so as to use them either fully or partially as anchoringcavities for anchoring the injected material therein.

[0022] A further advantage is that the subject anti-tampering seals arefirmly clamped in the cavities housing the molding material which,during the injection molding operation, will fill in any undercutsformed by the clamping nut thread and/or any slots formed in the screwcentering blind hole, or the roughness of said anchoring cavities.

[0023] A further advantage is that the molding material can comprise anydesired plastic materials or low melting metals or metal alloys. Byusing conventional or recessed nuts, it is moreover possible to reducethe height of the screw threaded portion, to provide a correspondingreduction of the required material amount. Even if small, such amaterial saving would be very important in a large series making saidball valves.

[0024] Yet another advantage is that the injection molding of saidfilling material is advantageously performed after having fullyassembled and possibly tested the valve, thereby the anti-tampering sealalso assure a perfectly reliable operation of the valve.

[0025] Yet another advantage is that the injection head, or injectionmolding head, has a simple bush shape and is removably fitted, by ageometrical type of engagement, on the valve locking nut/screw assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further characteristics, advantages and details of the improvedball valve according to the present invention will become more apparenthereinafter from the following disclosure of some embodiments thereof,which are shown, by way of an example, in the accompanying drawings,where:

[0027]FIG. 1 is a vertical longitudinal sectional view of an improvedball valve according to the present invention, taken along thecross-sectional plane 1-1 of FIG. 2;

[0028]FIG. 2 is a further cross-sectional view taken along the sectionplane ii-ii of FIG. 1;

[0029]FIG. 3 illustrates, on an enlarged scale, the detail A of FIG. 2;

[0030]FIG. 4 is a top plan view of the valve of FIGS. 1 to 3;

[0031]FIG. 4A is a detail top view showing the end portion of the drivelever of the ball valve of FIGS. 1 to 4;

[0032]FIG. 4B shows a detail like that of FIG. 4A of a simplifiedmodified embodiment of the geometrical fitting of the drive lever andvalve screw;

[0033]FIG. 5 is a perspective view illustrating the valve of FIGS. 1 to4;

[0034]FIG. 6 is a detail perspective view illustrating the clampingnut/screw assembly of FIG. 5, and the tampering seal therefor; and

[0035]FIG. 7 illustrates a detail like that of FIG. 6, showing amodified embodiment of the anti-tampering seal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Through the figures, like parts have been indicated by likereference numbers.

[0037] With reference to a prior ball valve 1, for example a gas ballvalve, it comprises a valve body 2 having an inlet 3 and an outlet 4, orvice-versa, and a chamber 6 arranged therebetween for housing therein aball shutter 7 having a throughgoing hole 8 supported by oppositegaskets 9 and engageable by a driving screw 11 thereon can be assembled,by a geometrical type of engagement, a drive lever 12 to be clamped onsaid screw 11 by a clamping nut 13.

[0038] As shown in FIG. 4, for geometrically engaging said lever 12 andscrew 11, the latter comprises, in the shown embodiment, two oppositeflat portions 14, 16, while the lever 12 comprises a correspondingrecess 17, see FIG. 4A.

[0039] At the threaded end portion 18 of the screw 11 an axial blindbole 19 is moreover provided Upon assembling the clamping or locking nut13 on the threaded end portion 18, between said screw 13 and flatportions 14, 16 of the screw 11, two chambers 21, 22, closed at thebottom by the top side of the lever 12 and, leading, at the top thereof,to the outside, are formed.

[0040] Said screw 11 and lever 12 can also be geometrically mated byusing a single flat portion on the screw, for example the flat portion14, to provide the recess 17A in the lever 12 with the configurationshown in FIG. 4B.

[0041] Said engagement of the screw 11 and lever 12 can also be madewithout providing flat portions on the screw 11, but merely athroughgoing pin orthogonally passing through the engagement end portionof the lever 12 and the screw 11, in a not shown manner.

[0042] Starting from the above disclosed prior art valves, the inventionprovides to include therein an anti-tampering seal, specificallydesigned for indicating an occurred tampering, which is formed inanchoring or clamping cavities which advantageously can be eitheralready formed in said valves or can be specifically formed.

[0043] Reference is made at first to the anti-tampering seal providedfor valves of the type shown in FIGS. 1 to 5.

[0044] According to the invention, the subject anti-tampering seal 25 isformed by injecting an injectable or molding material into at least acavity of the assembly formed by the threaded end portion 18 of thescrew 11 and clamping nut 13, which at least an anchoring cavity cancomprise the axial blind hole 19. In the shown embodiment, the anchoringcavity. further comprises two opposite cavities 21, 22 adjoining saidblind hole 19, said cavities 19, 21 and 22 being all outward opened.Thus, by providing an injection head 26 adapted to be fitted on theclamping nut 13 and having a dome top 27, said cavities 19, 21 and 22will be held in a communicating relationship. Accordingly, by injectingan injectable material into said chambers, they will be continuouslyfilled in by said injectable material which, during the injection, willoccupy the cut-outs formed, for example at the thread portions of saidchambers 21 and 22 and possible annular slots 28 formed in the axialblind hole 19, as shown in FIG. 3. FIG. 3 shows moreover that the top 27of the injection head 26 allows to provide the seal 25 with an outerportion 29, in the form of a disc cap, which substantially cover theoverall outer face of the nut 13.

[0045] In the embodiment shown in FIG. 7, the injection head 26 forms adownward directed extension 29A of the cap 29, thereby providing a cupconfiguration, which will be much more visually apparent than that of aseal 25 having a dome outer portion 29, as shown in FIG. 6.

[0046] The teaching of the invention of forming an anti-tampering seal25 including three anchoring cavities, can be obviously also applied tovalves having anchoring cavities of different number and/orconfiguration, or to a different type of geometric fitting, as shown,for example in FIG. 4B.

[0047] In actual practice, anyhow, the injection of said injectablematerial will be performed by conventional plastic material or metalmaterial injection molding methods, for example for injecting lead, tinor alloys thereof, i.e. low-melting metals, thereby the injectingmolding apparatus and methods will not be herein disclosed in furtherdetails since they are well known to one skilled in the art.

[0048] Finally, it should be pointed out that the firm anchoringprovided by the invention also allows to reduce the height of prior nuts13 including a plastic material ring 13A, or use conventional orrecessed nuts, thereby reducing the heights of the anchoring cavities19, 21 and 22 and that of the threaded portion of the screw 18 with aconsequent decreasing of the material amount and machining steps forforming the screw.

[0049] It should be moreover apparent that the anti-tampering seal 25can also be made on an already assembled and tested valve, therebyproviding a very reliable valve.

[0050] In operation, an unthreading of the locking nut 13, or atampering of the valve 1, will break the seal 25, to detach its outerportion, having a cap shape in the illustrated embodiment, therebyrendering clearly visually detectable said tampering.

[0051] This visual detection capability can be further enhanced by usinga properly colored molding material, contrasting with the color of thelever 12 or valve body 2.

[0052] From the above constructional and functional disclosure, itshould be apparent that the invention allows to efficiently solve theabove mentioned aim and achieve the mentioned advantages. In actualpractice, in addition to using the above mentioned anchoring cavities,it would be also possible to provide further anchoring cavities in thescrew/anchoring nut assembly, for example by forming a cross holepassing through the nut and screw, in a not shown manner, or providingthe cap portion with different shapes, without departing from the scopeof the invention.

[0053] In addition to gas system ball valves, the improved ball valvesaccording to the present invention can also be used in any applicationfields, such as in hydro-thermal-sanitary systems.

1. An improved ball valve, in particular for gas systems, comprising avalve body with an inlet and an outlet and a chamber arranged betweensaid inlet and outlet for housing a ball actuator supported by oppositegaskets and adapted to be engaged by a driving screw thereon is mounted,by a geometrical type of engagement, a drive lever, which can be lockedon said screw by a clamping nut, characterized in that in at least ananchoring cavity (19; 21; 22), provided either individually or incombination in the assembly formed by the threaded end portion (18) ofthe screw (1) and the clamping nut (13), an injectable molding materialtampering indicating seal (25) is formed which is injected into said atleast a cavity (19; 21; 22) and having a well visible, i.e. largesurface, outer portion (29).
 2. An improved ball valve according toclaim 1, characterized in that said anchoring cavity is formed by anaxial blind hole (19) extending in said threaded end portion (18) of thescrew (11) and leading to the outside.
 3. An improved ball valveaccording to claims 1 and 2, characterized in that said anchoring cavityfurther comprises at least a further cavity (21 or 22) adjoining saidaxial hole (19) and formed between an outer flat portion (14 or 16) ofthe screw (11) and the inner threaded surface of the clamping nut (13)clamped on said screw (11).
 4. An improved ball valve according toclaims 1 and 2, characterized in that said anchoring cavity furthercomprises two adjoining and opposite cavities (21, 22) formed by twoouter opposite flat portions (14, 16) of said screw and the innerthreaded surfaced of said clamping nut (13) clamped on said screw (11).5. An improved ball valve according to one or more of the precedingclaims, characterized in that the well visible outer portion of thetampering indicating seal (25) has a cap disc-like shape (29)substantially covering the outer free of said clamping nut (13).
 6. Animproved ball valve according to claim 5, characterized in that saiddisc-like cap (29) downward perimetrically extends on said clamping nut(13).
 7. An improved ball valve according to one or more of thepreceding claims, characterized in that said clamping nut (13) compriseseither a conventional or a recessed clamping nut.
 8. An improved ballvalve according to one or more of the preceding claims, characterized inthat said material, to be applied by injection molding methods or thelike methods, comprises a plastic material or a low melting metal ormetal alloy such as tin, lead or alloys thereof.
 9. An improved ballvalve according to one or more of the preceding claims, characterized inthat said material forming said tampering indicating seal (25) iscolored in a color contrasting against the color of said drive lever(12) and/or said valve body (2).